.each() add an attribute to a parent from jquery to js

try this : backs.length and tile_array.length are same .so no need ah inner loop

for (let i = 0; i < backs.length; i++) {
        backs[i].classList.add(tile_array[i]);
        backs[i].parentNode.setAttribute("data-name", tile_array[i]);
   }

And add a class in querySelectorAll('.back')